DNA organization in human spermatozoa

Division of Urology, Robert Wood Johnson University Medical School, New Brunswick, New Jersey 08903-0019.
Journal of Andrology (Impact Factor: 2.47). 03/1994; 15(2):139-44. DOI: 10.1002/j.1939-4640.1994.tb00419.x
Source: PubMed


Previous studies from this laboratory on hamster spermatozoa have demonstrated that rodent sperm DNA is packaged into the sperm nucleus in a specific manner by nuclear structures. The entire genome is organized into DNA loop domains attached at their bases to a sperm nuclear matrix, the skeletal structure of the nucleus. When nuclei are completely decondensed, the nuclear matrix dissipates, and the entire genome remains anchored to a single structure located at the base of the tail, termed the nuclear annulus. Here, we have extended these studies to human sperm nuclei, which were found to be similar to hamster. Human sperm DNA was found to be organized into loop domains attached at their bases to a nuclear matrix. The average size of the human sperm halo of DNA surrounding the extracted sperm nucleus (made up of DNA loop domains) was about 50% smaller than those that have been reported for somatic cells (this corresponds to an approximate loop domain size of 26.8 +/- 2.1 kb). Human sperm DNA also remained anchored to the base of the tail when completely decondensed, indicating the existence of a nuclear annulus-like structure in human spermatozoa; but, unlike the hamster nuclear annulus, the human annulus could not be isolated because of its structural instability when separated from the tail. Using human centromere repeats as a probe for in situ hybridization, we examined the packaging of individual DNA sequences within the sperm nucleus. These studies demonstrate that human sperm DNA is highly organized by nuclear structures.

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Available from: W. Steven Ward, Oct 13, 2014
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    • "These processes are associated with marked changes in the structure of the sperm chromatin (D'Occhio et al., 2007). As spermatogenesis proceeds, 85% of the histone nucleoproteins are replaced by transition proteins, which are subsequently replaced by small, arginine-rich proteins known as protamines (Oliva and Dixon, 1990; Barone et al., 1994; Balhorn et al., 2000). These changes give a compact, denaturating-resistant structure to the chromatin. "
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    ABSTRACT: Seminal proteins can be considered as factors that control fertilization. Clusterin is one such protein that has been implicated in many activities, including apoptosis inhibition, cell cycle control, DNA repair, and sperm maturation. In this study, the relationship between human secretory clusterin in seminal plasma with sperm parameters, protamine deficiency, and DNA fragmentation was investigated. Semen samples were collected from 63 Iranian men and semen analysis was performed according to World Health Organization criteria and Computer Aided Semen Analysis (CASA). The concentration of secretory clusterin (sCLU) in seminal plasma was measured by enzyme-linked immunosorbant assay (ELISA), protamine deficiency was determined by chromomycin A3 staining, and sperm DNA fragmentation was checked by sperm chromatin dispersion. The level of sCLU in seminal fluid of fertile patients was 48.3 ± 38.6 ng/ml and in infertile patients was 15.5 ± 9.7 ng/ml, and the difference was significant (p < 0.001). sCLU was correlated negatively with protamine deficiency, sperm DNA fragmentation, and abnormal morphology. In conclusion, seminal clusterin can be considered a marker for quick assessment of semen quality in male infertility studies. Mol. Reprod. Dev. © 2013 Wiley Periodicals, Inc.
    Full-text · Article · Jun 2013 · Molecular Reproduction and Development
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    • "Here we present the first genome-wide MCB-based study on 3D-preserved interphase nuclei derived from sperm (Fig. 1). Previously, comparable FISH-studies on sperm were performed on flattened nuclei with the known disadvantages of possible artifacts due to transformation of a spherical into a pancake-like object [11,24-26] or even on decondensed nuclei with DNA looping out [27,28]. As for probes, the ones used were: whole, or arm-specific chromosome paintings, or centromeric probes [23-29]. "
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    ABSTRACT: Nuclear architecture studies in human sperm are sparse. By now performed ones were practically all done on flattened nuclei. Thus, studies close at the in vivo state of sperm, i.e. on three-dimensionally conserved interphase cells, are lacking by now. Only the position of 14 chromosomes in human sperm was studied. Here for the first time a combination of multicolor banding (MCB) and three-dimensional analysis of interphase cells was used to characterize the position and orientation of all human chromosomes in sperm cells of a healthy donor. The interphase nuclei of human sperm are organized in a non-random way, driven by the gene density and chromosome size. Here we present the first comprehensive results on the nuclear architecture of normal human sperm. Future studies in this tissue type, e.g. also in male patients with unexplained fertility problems, may characterize yet unknown mechanisms of infertility.
    Full-text · Article · Dec 2008 · Molecular Cytogenetics
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    • "The chromatin structure of mammalian sperm nuclei differs significantly from that of somatic cells (Barone et al. 1994; Churikov et al. 2004; Steger et al. 1998). In the course of spermiogenesis, the extremely compact chromatin structure of mature spermatozoa (Poccia 1986) is formed by the replacement of histones by the transition proteins TP1 and TP2, which themselves are in turn replaced by protamines (Steger et al. 1998; Wouters-Tyrou et al. 1998). "
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    ABSTRACT: In spermiogenesis, spermatid differentiation is marked by dramatic changes in chromatin density and composition. The extreme condensation of the spermatid nucleus is characterized by an exchange of histones to transition proteins and then to protamines as the major nuclear proteins. Alterations in DNA topology that occur in this process have been shown to require the controlled formation of DNA strand breaks. Poly(ADP-ribosyl)ation is a posttranslational modification of proteins mediated by a family of poly(ADP-ribose) polymerase (PARP) proteins, and two family members, PARP-1 and PARP-2, are activated by DNA strand breaks that are directly detected by the DNA-binding domains of these enzymes. Here, we show for the first time that poly(ADP-ribose) formation, mediated by poly(ADP-ribose) polymerases (PARP-1 and presumably PARP-2), occurs in spermatids of steps 11-14, steps that immediately precede the most pronounced phase of chromatin condensation in spermiogenesis. High levels of ADP-ribose polymer were observed in spermatid steps 12-13 in which the highest rates of chromatin nucleoprotein exchanges take place. We also detected gamma-H2AX, indicating the presence of DNA double-strand breaks during the same steps. Thus, we hypothesize that transient ADP-ribose polymer formation may facilitate DNA strand break management during the chromatin remodeling steps of sperm cell maturation.
    Full-text · Article · Jun 2005 · Chromosoma
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